(a) Field of the Invention
The present invention is related to a structure of a spray gun head, and more particularly, to one that prolongs the service life and easier service of the spray gun head by modifying internal members that control airflow.
(b) Description of the Prior Art
As illustrated in FIG. 3 of the accompanying drawings, the prior art spray gun, includes a spray gun head (1), a nozzle body (3), an air cap (4) and a locking ring (5). Wherein, the spray gun head (1) contains a ring bearing (11), with the outer periphery of the ring bearing (11) being provided with a threaded section (111), and a vent hole (12). A nozzle carrying tube (13) is extended from the center at the base of the ring bearing (11). The vent hole is connected through to an inlet of low pressure air (16), and a threaded section (131) is provided inside the bore of the nozzle carrying tube (13) to be screwed to the nozzle body (3). A needle valve (17) is inserted to the other end of the nozzle carrying tube (13) with the needle valve (17) holding against the center of the nozzle body (3) and penetrating through a paint spreader hole (36). A pillar (31) is provided in the rear section of the nozzle (3) and a nozzle (32) is provided at the front end of the nozzle body (3). An air guide ring (33) is provided at the outer diameter of the pillar (31) and a plurality of airflow guide holes (34) are provided on the surface of the airflow guide ring (33). A threaded section (311) is provided at the terminal end of the pillar (31) of the nozzle body (3) corresponding to the threaded section (131) on the nozzle carrying tube (13). A hole (41) is provided at the center of the air cap (4) and a plurality of firstjets (42) and secondjets (43) are separately provided on the outer circumference of the air cap (4). A flange (44) protrudes from the inner side of the air cap (4). The locking ring (5) is a hollow ring cover and provided a threaded section (51) on the inner wall. The pillar (31) of the nozzle body (3) is screwed to the nozzle carrying tube (13) by engaging the threaded section (311) of the pillar (31) to the threaded section (131) of the nozzle carrying tube (13). The airflow guide ring (33) of the nozzle body (3) covers up the ring bearing (11) of the spray gun head (1) and the air cap (4) covers up the nozzle body (3). The nozzle (32) is exposed out of the hole (41) in the center of the air cap (4) and the locking ring (5) is screwed to the ring bearing (11) of the spray gun head (1) to lock and compress against the nozzle body (3) and the air cap (4) by holding against the flange (44) of the air cap (4). An air port space is formed between the nozzle body (3) and the spray gun head (1). By turning the locking ring (5) clockwise or counter-clockwise, the air port space as well as the air pressure between the firstjets (42) and the second jets (43) are regulated as desired. However, air pressure respectively from the first jets (42) and the second jets (43) is practically the same and that prevents easy regulation. Therefore, the nozzle could get easily blocked to shorten its service life and the blocked nozzle makes its clean maintenance extremely troublesome.
The first purpose of the present invention is to provide a spray gun head containing two units of air ports, and a diverter bushing that is capable of providing longer service life for the spray gun head and easier service of the spray gun head. To achieve the purpose, the present invention comprises a spray gun head, a diverter bushing, a nozzle body and an air cap; characterized in that a first vent hole and a second vent hole are separately provided in the spray gun head. The diverter bushing provides a plurality of jets in relation to the first vent hole of the spray gun head to form a first air port. The nozzle body provides an airflow guide ring having a plurality of airflow guide holes in relation to the inner wall of the diverter bushing to form a second air port. A plurality of first jets and second jets are provided in the air cap which guards the nozzle body. Air from the first and the second vent holes flows by following the first air port, the second air port, the diverter bushing and the airflow guide holes in the airflow guide ring to respectively eject out of the corresponding first and second jets in the air cap.